> ## Documentation Index
> Fetch the complete documentation index at: https://docs.base.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Submit signed transactions that Base considers when onchain conditions match.

Validity Transactions let you submit a signed transaction with conditions on Base state. The API supports legacy, EIP-2930, and EIP-1559 transactions; EIP-1559 is recommended. Use them for conditional swaps, withdrawals, and other state-dependent actions.

<Warning>
  Validity Transactions are experimental. `base_sendRawTransactionValidity` is currently available on Vibenet. Mainnet and Base Sepolia availability are not yet confirmed.
</Warning>

## How It Works

Submit a signed raw transaction and a non-empty `validity` array. The current API supports balance, storage, block-number, and Flashblock-index predicates.

A transaction is eligible only when every predicate matches. Base checks predicates before inclusion. A pending transaction can become eligible after an earlier transaction changes the state it watches.

EIP-1559 Validity Transactions use normal fee fields. Eligibility does not reserve block space or guarantee inclusion.

## Lifetime and Privacy

Use `block_number` or `flashblock_index` predicates to constrain when a transaction can be included. Use the sender's nonce when replacing a pending transaction.

Validity criteria are sent separately from the signed transaction. They do not appear in the resulting onchain transaction. Do not include secrets in calldata or predicate values.

## Next Steps

<CardGroup cols={2}>
  <Card title="Build a Validity Transaction" href="/specifications/build-transaction/build-a-validity-transaction" icon="hammer">
    Sign and submit a transaction with Viem.
  </Card>

  <Card title="Validity Transaction RPC" href="/specifications/build-transaction/base_sendRawTransactionValidity" icon="code">
    Review the request format.
  </Card>

  <Card title="Fees, Ordering, and Lifecycle" href="/specifications/build-transaction/fees-ordering-and-lifecycle" icon="arrow-down-1-9">
    Understand fees, expiry, and replacement.
  </Card>

  <Card title="Predicates and Safety" href="/specifications/build-transaction/predicates-and-safety" icon="shield-check">
    Learn predicate rules and safety limits.
  </Card>

  <Card title="Troubleshooting" href="/specifications/build-transaction/troubleshooting" icon="screwdriver-wrench">
    Diagnose submission and inclusion issues.
  </Card>
</CardGroup>